I just set up Exim for sending email from a website using this guide: http://library.linode.com/email/exim/send-only-mta-ubuntu-10.04-lucid
All done with no problem.
When I open a test mail I sent to myself, in the "from" field, instead of showing only the website's address, it also shows my server's hostname.
I read the explanation from Gmail but can't figure out: https://mail.google.com/support/bin/answer.py?hl=en&ctx=mail&answer=1311182
How could I hide it?